One problem faced by a radiologist, surgeon or other medical practitioner when inserting a medical instrument (device), such as a trocar, biopsy punch or biopsy needle, into a patient's body during MRI procedures is the difficulty of correlating the appropriate external position of the instrument to assure contact with the desired internal structure. The problem of correlation can also cause inadvertent contact of the instrument with an unintended internal structure.
Diagnostic imaging modalities such as magnetic resonance tomography (MRI) provide diagnostic images which show the location of an anatomical structure or location in a patient's body. Often times, however, it is difficult to transfer the point obtained from the image onto the body's contour. Accordingly, there is a need for a system to correlate an external body location with a particular internal site. There is also a need for a system to provide accurate positioning of a medical instrument on a patient's body to contact a desired internal point.